My low coolant light comes on a few minutes after I start driving. on 2002 Saturn LW300

I have checked the coolant level and it is normal both when engine is warm and when it is cold. The engine temp guage always remains the same. Any suggestions?

Asked by for the 2002 Saturn LW300
The sensor may be malfunctioning and need replacement.
Thanks. I have been looking for a replacement sensor for the coolant level and cannot find one. Will I need to buy a whole new overflow tank? I would rather replace it, but cant find the sensor listed with any parts stores. Any suggestions?
1 more answer , 2 more comments
The level sensor probaly needs replaceing.
Any ideas where I could find one. They arent even listed at any online parts stores for my car.
The aftermarket parts comanys do not make that part. It would need to come from the dealer. It should be checked first to make sure that is truly the problem.